This invention relates to the field of metal refining. More particularly, this invention relates to a new and improved process and apparatus therefore for the metallurgical refining of steel in a ladle or similar vessel.
For several years, the steel industry has increasingly utilized ladles for a variety of metallugical processes. The more frequent use of these ladles has come about, in part, because of the recent development of continuous casting. Thus, the metallugical processes conventionally intended for the steel converter or electric oven prior to delivery to the casting equipment are now often being conducted in the ladle.
As noted, the refining processes conducted in the ladle are of various types and frequently include the following:
1. Processes involving dephosphorization; PA0 2. Processes involving desulphurization via the injection of metallic desulphurizing materials such as calcium-silicon, Perrin slags or other slags consisting of lime and/or fluorspar. Other desulphurizing agents such as magnesium or calcium carbide have also been used. These injections are usually effected by entrainment in an inert or reducing carrier gas; PA0 3. Deoxidation processes carried out by the addition or injection of aluminum, ferro-silicon, calcium-silicon, etc. Note that the processes of desulphurization and/or deoxidation can be combined; PA0 4. Processes of heating by electric arc or by induction; PA0 5. Processes of refining or purification of steel, either by vacuum or by simple bubbling with or without the addition of slags.
For a number of years, the assignee of the present invention has spent considerable efforts on developing and improving the above methods and has acquired particular expertise in regulating and controlling the metallugical reactions between the slag and the melt.
Pursuant to this extensive research and development, it has been unexpectedly discovered that the formation of certain reactive slags within the ladle will result in an acceleration and an improvement in the dephosphorization, desulphurization, deoxidation and purification processes discussed above while simultaneously permitting an easily manageable or controllable increase in the temperature of the metallic bath. These reactive slags are prepared via a combustion process by reacting oxygen with certain metals and subsequently adding other nonmetallic compounds.